Method and means for reproducing and printing wood grains and the like



June 22; 1937.. v, E MARIA ET AL 2,084,792

I METHOD -AND MEANS FOR REPRODUGING AND PRINTING WOOD GRAINS AND THE LIKE} Filed June 17, 1933 hak GZweZ W 7150(5 Y iy 1 21527502 INVENTORS VNCENT DE MARIA. lRabgA STANKOVITS KlSS UNI-E1 Patente June 22, 193? Vincent De Maria, Asbury Park, N. J., and Irma Stamkovits Kiss, New York, N. Y.

Application June 1'], 1933, Serial No. 676,310

so STATES PATENT orrics 18 Claims.

The improvements relate primarily to means and methods for reproducing and printing, on the surface of sheet material and on various other surfaces, natural wood grains and patterns and other natural objects and to thus provide a less expensive, quicker and more faithful and attractiveimitation or duplication. They and the various phases thereof inay be used however for l any other purpose to which they are adaptable. 'Among theobjects of the improvements are I to provide a more exact simulation of the natural object to permit the use of less costly means and methods to this end, and to secure these results in unusually large sizes when desired. The various steps employed in obtaining these advantages are in themselves improvements, including the making of.- the plate from which printing of the subject is accomplished, the etching of these plates so as to obtain increased durability and emciency, the mounting .of them, and their inking and printing. Other objects and advantages will be apparent to those skilled in the art from the following description.

1 Heretofore it has been the practice in repro- 25, ducing and printing wood grains to make a halftone or lineengraving of the original natural wood on a flat metallic plate, by well known methods or to produce a similar plate in intaglio and print from it by using a transfer roller to 30 take the ink therefrom and print it on the metallic or other surface to be decorated therewith, after the plate has been inked and sub: jected to the action of a doctor blade, the transfer roller being cleaned after each printing operation. r

Half-tone plates, in addition to their high cost of manufacture, necessitate the useof a crossline screen, thereby oifering two serious disadvantages: first, because these screens are obtainable only in comparatively small sizes, and therefore they place a definite limitation upon the size of plate which can be produced, and

second, because unless, 'a screen of very fine mesh is used, the resulting reproduction is not only 45 imperfect but is of a displeasing pattern. On the other hand the use of a screen of suitably fin'e' mesh requires expensive materials, highly skilled-labor, and lengthy ,manlpulations, thus -adding very considerably to the already high cost 50 of manufacture. Line engravings involve a large amount of expensive hand work in attempts to imitate the various gradations of tone by means of lines ofsuitable lengths and thicknesses properly placed. This is at best productive of a 55 crude, artificial appearance, in which a large part of the natural beauty of the wood or other original is lost. The intaglio plate is limited in size by the size of the screen which is necessary to reproduce tonal gradations, is costly to produce, artificial in appearance, and involved in its application, due to the unavoidable transfer roll and doctor blade operations.

Rigid metallic plateshave sometimes been ap plied to rollers in cylindrical form and used with inking devices and doctor blades and in connection with a transfer roll, but this does not overcome the inherent objections to work of this character. So far as we are aware wood grains have never before been reproduced on a resilient relief plate which can be used without transfer means to print directly on the surface-usually metal-to be decorated. Nor has such a plate been mounted on an elastic roller, which permits I it in printing to accommodate itself to slight irregularities in the surface to be printed, and enables the operator to print a substantially perfect reproduction of the wood without the flaws and inaccuracies due to other methods. So far as we are aware no printing plate has heretofore been produced in which the grain and pattern ofv the wood is brought out substantially in its natural strength, depth and detail and without sharp, harsh or other undesirable lines.

The accompanying drawing illustrates the printing rollers and the printing plate of our improvements, the illustrations of the engraved or etched portion of the plate and of the etched portion of the roller being conventional, as it is not possible to ,reproduce the same in a pen and ink drawing evenon a magnified scale such as that of the drawing. In the said drawing Figure 1 is a plan of a fragment of the plate and of the engraved periphery of the roller of Figs. 5 and 6 projected on a horizontal plane; Figure 2 is a vertical section on the line 2-2,.of Fig. 1; Figure 3 is a longitudinal medial section of the roller with printing plate thereon; Figure 4 is a diagram of a vertical cross; section of the roller of Fig. 3; Figure5 is a longitudinal medial section of the roller withengraved outer layer; and gure 6 is a diagram of a vertical cross secion of the roller of Fig. 5.

In carrying out the present improvements, a fiat panel of natural unstained wood of pleasing pattern is first taken and treated if necessary by well known methods for accentuating its flne f details. A photographic negative is then made,

and since a certain amount of coloris inherent in the natural grain, a color sensitive plate with a'cqmpensating colorfllter interposed between it and the original is used to further emphasize the finest tones by eliminating the last vestige of color.

Next a master negative is made which can be used indefinitely to make an unlimited number of printing plates, which latter are used for the purpose of applying the picture of the natural wood to the surface to be decorated therewith. Since this printing plate is to be of gelatin, and is to permit of surface or relief impressions instead of sub-surface or intaglio, such as are made from the regular collotype or intaglio gravure plates, it is necessary that the master plate embody in itself a grain or web for the lcpurpose of breaking up the continuous tones and allowing of their faithful reproduction. In other words, the grain plays a part similar to that of a cross-line screen used in half-tone work.

We have discovered that such a grain, web, or 20 screen can he arrived at-by employing a cer tain combination of chemical and mechanical treatment of the gelatin which is carried on through the operations of preparing, sensitizing, exposing and etching. The next step, therefore, 25 is to coat a suitable glass or other plate with a mixture consisting of gelatin, albumen, ammonium bichromate, nitrate of silver, calcium chloride and water. To do this we take 16 ounces of gelatin such as is used for photographic emul- 30 sion purposes, and one gallon of distilled water and soak the gelatin in the distilled water for about twelve hours at a low temperature, preferably between 35 and 40 F. so that the gelatin will absorb its full quota of water. We then place -35 this in a. jacketed pan and add 32 ounces of albumen, applying heat very gradually to raise the temperature to a degree sufiicient to coagulate the albumen, stirring gently during the heating process. The mixture is then filtered carefully 40 with the aid of a jacketed funnel to remove albumen and the foreign matter therein from the gelatin. Two ounces of'ammonium bichromate ['(NH4) zCraO'z] in 50 ounces of water-a4 per cent. solutionis now added, and when this is thoroughly mixed, 56 ounces of a 2 per cent. water solution of nitrate of silver (AgNOa) is added.

It will be found that the solution has now taken on a red color, and enough of a 6% per 50 cent. solution of calcium chloride (CaClz) in water is added (about 2 ounces should be sufificient) to dispel this color. It is important that the various additions be made slowly and with constant stirring. Finally 100 minims of acetic acid and 145 minims of glycerine are stirred in and the whole filtered. Theplate, which should be at about the same temperature as gelatin, is now coated with this substance.

After the plate is coated it is dried at a moderately high temperature (100-120 F. is suitable) in a still oven, and when dry is exposed behind the color corrected negative which has been prepared from the original wood. After exposure, the plate is washed in the usual manner, and 65 after a certain time of immersion it will be found that the coating has taken on a granular appearance, which is due to the silver combining with the chromate to make silver chromate and the efiect of thebaking action on the gelatin impregnated with such silver chromate. This grain is very fine and of a pleasing quality and is controllable as to size by the thickness of the coat employed, by a variation of the chemicals, such as an increase of the calcium chloride and/or 75 by washing after the photograph c exposure in ted through the negative.

water at normal atmospheric temperature to make the grain coarser or more open. It is however so fine, that it is not visible to the eye of the ordinary observer, but produces the effect of the original wood. The grain will be seen to have somewhat the efiect of a fine half-tone screen, but will not materially flatten or take away from the depth and natural clarity of the original wood grain.

All of the steps relating to the preparation of the plate coating, coating of the plate and washing should be done in a dark room,and' the exposure behind the negative should be by artificial' light, so as to ensure accuracy of exposure.

A similar plate having a somewhat similar effect, but with less satisfactory results may be made by making a color-sensitive collodion emulsion negative from the original wood, then making a drawing from this negative on stippled drawing paper by projecting the negative on the paper, using a regular enlarging camera and drawing in the pattern of the wood as transmit- The shadings and various tones are carefully reproduced; and since this drawing is to be a positive or original, those parts which through the negative appear clear 'or white are pencilled in darkest, the depth of the other tones assuming the same proportion to each other as on the original wood. An ordinary collodion wet plate is now made from the stippled drawing, which plate becomes the master negative. The procedure followed for making final printing plates from this master negative is the same as that given below for making these plates.

The next step in the original process is to ink the plate and make a transfer in the usual method employed by lithographers, except that the transfer is made on to a specially prepared sheet of smooth-surfaced, impervious board such as transite, which has been coated with a layer 'of Chinese or other suitable white, and covered with duco or other suitable lacquer. The object of the white coat is to afiord greater contrast between the picture of the wood and the background, thereby separating the grain more sharply and emphasizing the details.

The process is now further carried on by making another negative of the subject printed on the transite board, this time using a wet plate which is coated on -a glass plate of a quality that will not absorb ultra violet rays, to cut down the time of exposure. on the final printing plate (as 7 from 4 minutes to 1 minute). In making this negative, the subject is enlarged sufliciently, for ordinary work, so that the grain screen or web now embodied in the picture as hereinbefore described will be comparable to an 85 or 100 crossline screen. We have now completed a master negative with granular efiect from which all printing plates of that particular wood will be made.

The next step is the preparation of the final printing plate. This plate is eventually ,mounted on and united with a flexible elastic composition roller preferably made of glue, balsam of fir, molasses and glycerine, or other suitable composition, and the plate therefore can be coated onto a glass plate and later stripped therefrom and annealed to the roller, as will be explained later, or it can be coated on a flexible support such as canvas or celluloid. Should a glass plate be used, a preliminary coat of oxg'all/(commercial, for various purposes), is applied to facilitate the stripping later on.

, of sugar and 2 ounces of glycerine, 20 minims of phenol (CsHsOH) is added as a preservative. The mixture now has a bright orange color, and sufdcient ammonia is added to change this to a lemon yellow. We then filter carefully and apply to the plate, which is allowed to dry spontaneously. When dry it is exposed behind the master negative made as heretofore described.

Since it is our object to obtain a printing plate which will make the impression from its surfaces instead of from its recesses,it is desirable to have a" high relief which will be of permanent quality and not require the use of damping solutions such as are necessary'in collotype. We have found that this can be accomplished by treating the exposed gelatin plate with a dilute acid solution, such as a 10 per cent. nitric or sulphuric acid solution, the action being similar to the action of acid on metal in photo engraving. The acids will eat away the parts which have not been touched by light and will allow to stand in relief those portions which have been acted upon and hardened by the light. One half hour with a 10 per cent. solution of nitric acid will give suflicient depth for printing, and greater depth can be obtained by a longer period.

It is advantageous to accelerate the exposure of the sensitive plate by employing arc lamps equipped with special carbons giving a light rich in ultra violet rays. Those known commercially as Suntan are especially suitable. Sunlight would, of course, be ideal, but its quantity and, quality are so variable that its employment is not commercially practicable.

If the printing plate has been coated on to a flexible support it can now be wrapped around the composition cylinder and its meeting ends turned in to engage snugly in a slot in the composition elastic layer and the rigid core. If on the other hand it has a glass 'or metallic sup port, the coating is stripped off while still wet and annealed to the composition roller with the aid of a controllable jet of hot vapor, at a temperature of 100 degrees or a little more, ,which dissolves the surface .of the composition layer sufficiently to allow, upon cooling, the adhesion of the back of the plate to the said surface. We now have a permanent printing plate on a cylinder ready for use.

To make the continuous printing roller, that is, one without the break in the design which is necessarily caused by the fact that the ends of the printing plate on the roller merely meet but are not joined, the following procedure is adopted. A wooden or other substantially rigid cylindrical core is first coated with a flexible composition such as that hereinbefore described and is then placed in a cylindrical vessel having a depth equal to the length of the core, the vessel having its bottom end closed and being maintained in an upright position and the roller being centered therein so as to leave an annular space between it and the inner wall of the vessel of about of an inch, the vessel being sufficiently greater in internal diameter t the diameter of the roller to provide for this space. The sensitized gelatin solution is now poured into the annular space until the space is filled, the pouring operation being conducted carefully and without such agitation of the fluid as will form froth or bubbles. In this manner also cylinders may be formed having irregular longitudinal lines for printing on irregular surfaces, such as pedestals, posts and lamp'shades.

In this case, however, it is necessary to make the outer cylinder or mold opena'ble, so that the molded cylinder can be removed. After they molded cylinder has set it is removed from the outer cylinder and dried spontaneously, and it is then ready for exposure 'in a special camera designed for that purpose.

For use in the formula making the sensitive coat for the roller dichromate of the highest purity should be employed, as any impurities will interfere with the high relief necessary for surface printing to a greater or less extent. It is also desirable to add to the mixture, before adding the sugar and glycerine, and after it is thoroughly dissolved, about one-half ounce of cerium chloride (CeClz) which has been dissolved in 10 ounces of water. All this work must, of course, be carried on in dark rooms, and the sensitized film or plate should be used at once, as deterioration sets in promptly.

The formula productive of best results in the preparation of the elastic roller layer which forms a backing or blanket for the printing surface consists of fish glue, 3 parts, balsam of fir, 2 parts, glycerol of specific gravity 1.260 to produce the required resiliency and water 1 part, these proportions being by weight. This mixture is then heated to about 100 F. or a little more and until it becomes liquid and when thoroughly mixed, it should be poured slowly into a zinc cylinder, in which the core has first been positioned centrally, so as to leave the desired annular space between it and the wall of the mold,

and then allowed to set. In this operation, it is with gelatin and pi ment sensitized with potas slum dichromate. When the positive has been made, it is stripped off the paper support and transferred on to a glass plate. A paper negative of the required size is now made by projecting the positive by the conventional enlarging method, with one important change-the manner of illumination. It is common knowledge that in making enlargements, the grain of the subject being enlarged is very much accentuated due to present imperfect lighting methods; and since it is desirable in this particular instance that there be no grain visible but that which has been chemically arrived at as previously described, we have found that an indirect method of lighting is productive of the required results. The details of this method will be fully set forth in a copending application.

We now have a negative on paper, which is fastened on to a cylinder of the required diameter so that the two ends will meet as accurately as possible. The remaining crevice or joint may be carefully filled in and retouched in such a way as to make the pattern continuous, if desired.

The negative just described now becomes the master original negative cylinder from which all continuous printing cylinders are exposed for the reproduction of one particular wood grain.

The master'negative may then be exposed on to the sensitized roller through the lens by rotating the two cylinders in opposite directions by means of a pair of synchronized motors, each motor rotating one of the cylinders as will be fully described in a copending application. The sensitized roller may also be exposed in contact, but for this purpose the master negative is made on celluloid instead of paper. The negative in this case is wrapped around the sensitive roll and exposed. For obvious reasons, the contact method may only be employed when a continuous roller, that is one without any visible break, is not necessary.

The lighting of these rolls for exposure is accomplished by means of special arc lamps. The

light from these lamps is so controlled that they project long, narrow beams which expose only that portion of the revolving cylinder which is directly before the lens. The construction ,of these special lamps will be more fully described in a copending application.

The exposed sensitized roll is now etched in the manner described above for fiat plates, and this is best carried out in a special tank provided for that purpose. The result is a permanent, continuous printing roller ready for use.

In printing from the plate prepared as herein described, any good half tone ink may be used. The printing operation may be carried on by mounting on the projecting axis of the roller so as to contact with the surface of the plate a suitable inking roller having an ink fount with an-intermediate roller to transfer ink from the fount to the said inking roller and causing the printing roller to roll over the sheet of metal or other object to be printed, which causes the ink to be first applied to and distributed on the surface of the cylindrical printing plate of the periphery of the printing roller and then causes the said printing plate to print on the object to be printed. The object to be printed upon is guided on a supporting bed and the printing roller rolled over it slowly and carefully to produce a perfect impression, or it may be passed under the printing roller and in contact therewith and over an underlying roller adjusted to the proper position and rotating on a fixed axis. In this case the printing roller is also mounted on a fixed axis in vertical alignment with the axis of the bearing roller beneath the plate. A suitable table for supporting the object to be printed upon, with guides to hold it against all lateral motion while being printed should also be employed. The weight of the printing roller gives suflicient pressure in larger sizes to make the impression, but if more pressure is required in any case the projecting axisof the printing roller may be weighted to the desired extent. The plate or other object to be printed upon should first be provided with a suitable base coating to form a backing for the printing and receive the ink impression, as metal does not take ink readily and does not provide a satisfactory background for decorations of the character in question in most cases.

It will be seen from the foregoing that by the present improvements at very durable and eflective aosa'rea non-metallic relief printing roller is provided and that this roller has suflicient elasticity to permit it to be brought into close contact with the plate or other object to be printed, regardless of any slight unevenness of the latter, and to impress a perfect reproduction of the original wood grain and pattern thereon.

What we claim is:

'1. The method of producing a printing device comprising a roller having a rigid core, a layer of elastic material on said core and concentric therewith and a sheet of non-metallic resilient material united with the exterior of said layer on its inner side bearing on its outer side an engraved relief pattern for printing, which consists in placing said rigid core in an annular mold of greater diameter and centering the same therein, then pouring the elastic material around said .core and allowing it to set, then wrapping and annealing the plate thereon.

2.'The method of producing a printing device comprising a roller having a rigid core and a layer of elastic material on said core and concentric therewith which consists in placing the core in a cylindrical mold of greater diameter and centering it therein, then sensitizing the elastic material and then pouring it around the core then making an engraved relief pattern for printing on the exterior of the layer of said material thus formed.

3. A method or process of producing a plate for printing reproductions of natural objects which comprises treating a gelatinous substance with ammonium bichromate, nitrate of silver and calcium chloride intimately mixed therewith, forming a film of the mixture, drying and exposing the same to light through a photographic negative of the object to produce a printable plate having a granular surface and then washing to remove portions of the film not exposed to light,

- the drying beingdone by baking the film at a printing the said plate on a smooth surface presenting a white background, then making from same photographically on a second plate and etching the latter.

5. A method or process of producing a plate for printing reproductions of natural objects which comprises treating a gelatinous substance with ammonium bichromate, nitrate of silver and calcium chloride intimately mixed therewith, forming a film of the mixture, then baking the film at a temperature below C., exposing the same to light through a photographic negative of the object then washing to remove portions of the film not exposed to light to produce a printable plate having a granular surface, then printing the said plate on a smooth surface presenting a white background, then making from said print a second negative and. printing the same photographically on a second plate and etching the latter, the said second plate comprising a light- .55 said print a second negative and printing the sensitive coat of gelatin and potassium dichromate.

6. A method or process of producing a plate for printing reproductions of natural objects which comprises treating a gelatinous substance with ammonium bichromate, nitrate of silver and calcium chloride intimately mixed therewith, forming a film of the mixture, drying and exposing the same to light. through a photographic negative of the object, the drying being done by baking the film at a temperature below 100 C., and then washing to remove portions of the film not exposed to light to produce a printable plate having a granular surface, then printing the said plate on a smooth surface presenting a white background, then making from'said print a secnd negative and printing the same photographically on a second plate and etching the latter, the second plate comprising a light-sensitive coat of gelatin and potassium dichromate, then washing the said second printing plate with a dilute acid solution to remove parts which have not been affected by light.

7. A method or process of producing a plate for printing reproductions of natural objects which comprises treating a gelatinous substance with ammonium bichromate, calcium chloride, and nitrate of silver intimately mixed therewith, forming a film of the mixture, baking the film at a temperature above 90 and below 200 F. and exposing the same to light through'a photographic negative of the object then washing to remove portions of the film not exposed to light, to produce printable plate having a granular surface.

8. A method or process, of producing a plate for printing reproductions of natural objects which comprises treating a gelatinous substance with ammonium bichromate, nitrate of silver and calcium chloride intimately mixed therewith, forming a film of the mixture, then baking the film at a, temperaturebelow 100 C. and exposing the same to light through a photographic negative of the object then washing to remove portions of the film not exposed to light and to produce a printable plate having a granular surface, then printing the said plate on a smooth surface presenting a, white background, then making from said print a second negative and printing the same photographically on asecond plate and etching the latter;

9. A method or process of producing a plate for printing reproductions. of natural objects which comprises treating a gelatinous substance with ammonium'bichromate, nitrate of silver and calcium chloride intimately mixed therewith,

. forming a film of the mixture baking the film at a temperature below 100 C., and exposing the same to light through a photographic negative of the object then washing to remove portions of the film not exposed to light and toproduce a printable plate having a granular surface, then drying the film at a-temperature below 100 C. and exposing the same to fight through a. photographic negative of the object then washing to remove portions of the film not exposed to light, to produce a printable plate having a granular surface, then printing the said plate on a smooth surface presenting a highly light reflective background, then making from said print a second negative and printing the same photographically on a second plate and etching the latter, the second plate comprising a light-sensitive coat or film of gelatin and a light sensitizing agent, then washing the said second printing plate with a dilute acid solution to remove parts which have not been afiected by light.

11. A method or process of producing nonmetallic relief plates for printing reproductions of objects such as natural wood which comprises the preparation of a blank light-sensitive plate by treating a gelatinous substance with a bichromate calcium chloride and nitrate of silver so as to produce silver chromate therein, exposing said plate through a color corrected negative of the object and then washing to remove portions thereof not affected by the light and leaving a granulated relief representation of the object, said granulations being produced by the action of said chloride, silver and chromate in the gelatin.

. 12. A method or process of producing nonmetallic relief plates for printing reproductions of objects such-as natural wood which comprises the preparation of a blank light sensitiveplate by treating a gelatinous substance with a bichromate, calcium chloride, and nitrate of silver so as to produce silver chromate therein, exposing said plate through'a negative of the object and then washing to remove portions thereof not affected by the light and leaving a granulated relief representation of the object, said granulations being produced by the action of said chloride, silver and chromate in the gelatin.

13. A method or process of producing nonmetallic relief plates for printing reproductions of objects such as natural wood which comprises the preparation of a blank light-sensitive plate by treating a gelatinous substance with a bichromate, calcium chloride and nitrate of silver so as to produce silver chromate therein, exposing said plate through a, negative of the object and then washing to remove portions thereof not affected by the light and leaving a granulated relief representation of the object, said granulations being regular and produced by the action of said calcium chloride, silver and chromate in the gelatin.

14. A method or process of producing nonmetallic relief plates for printing reproductions of objects such as natural wood which comprises the preparation of a blank light-sensitive plate by treatingagelatinous substance with a bichromate,

calcium chloride'and and nitrate of silver so as to chloride, silver and chromate in the gelatin, and

varying the character and spacing of said granulations to produce a relatively fine or coarse grain by adding to the mixture with the gelatin calcium chloride in varying proportions.

15. The method or process of producing a nonmetallic relief printing plate for the reproduction printing roller having a rigid core, a layer of elastic material on said core and concentric therewith and a sheet of non-metallic resilient material united with the exterior of said layer on its inner side and bearing on its outer side an engraved relief pattern for printing.

17. An article of manufacture consisting of a printing roller having a rigid core, a layer of aosavoa elastic material on said core and concentric therewith and a sheet of non-metallic resilient material united with the exterior of said layer on its inner side and bearing on its outer side an engraved relief pattern for printing, said printing plate being of non-metallic character and consisting essentially of a gelatinous body.

18. An article of manufacture consisting of a printing roller having a rigid core, a layer of elastic material on said core and concentric therewith consisting of a sheet of non-metallic resilient material united with the exterior of said roller on its inner side and bearing on its outer side an engraved relief pattern for printing, said printing layer being of non-metallic character and consisting essentially of a gelatinous body.

VINCENT DE MARIA. IRMA STANKOVITS KISS. 

